It is a common present-day practice to prefabricate the frames of domestic dwellings, and other houses and buildings, and preassembled roof trusses are in frequent use. The transport and handling of timber roof trusses sometimes incurs damage thereto as they are somewhat unstable before on site erection in a roof. For this reason, as well as to reduce the cost and/or increase the strength, efforts have been made to produce metal roof trusses. A recently developed metal roof truss now in use is often preferred to its timer predecessors. However, it is of hollow section and a welding operation is included in its production.